Diagnostic Biomarkers for Alzheimer's Disease Using Non-Invasive Specimens

Area of Science:

• Neurology
• Biomarker Discovery
• Diagnostic Technologies

Background:

• Early diagnosis of Alzheimer's disease (AD) is crucial for effective treatment, as interventions may be stage-dependent.
• Current AD diagnostic methods rely on cerebrospinal fluid (CSF) and blood samples, which are invasive.
• Oral samples like saliva and buccal cells are under-investigated yet offer a promising non-invasive alternative.

Purpose of the Study:

• To review existing research on the use of salivary and buccal cells for Alzheimer's disease detection.
• To analyze the analytical approaches and findings from studies utilizing oral samples for AD diagnosis.
• To assess the potential of oral biomarkers for early and non-invasive AD diagnosis.

Main Methods:

• Comprehensive literature review of studies investigating oral samples (saliva, buccal cells) for AD detection.
• Analysis of various analytical approaches including proteomics, metabolomics, spectroscopy, and microbiome analyses.
• Evaluation of reported biomarkers such as amyloid beta (Aβ), total tau (T-tau), and phosphorylated tau (P-tau) in oral fluids.

Main Results:

• Proteins like Aβ, T-tau, and P-tau, along with small metabolites, have been detected in saliva.
• Oral samples have demonstrated potential as future diagnostic markers for AD.
• Most studies reviewed were conducted on small cohorts, leading to some contradictory results and difficulty in drawing definitive conclusions.

Conclusions:

• Oral samples present a viable non-invasive option for AD diagnosis, with detected biomarkers showing promise.
• Standardization of sample preparation and analytical methods is essential.
• Large-cohort studies are required to validate the diagnostic utility of oral biomarkers for Alzheimer's disease.